Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Que dia ele jogou no modo difícil com Tom Mercer?
 ###Tabelas: CREATE TABLE torneo_clausura (torneo_clausura_id AUTO_INCREMENT PRIMARY KEY, Position INT, Team VARCHAR, Played INT, Wins INT, Draws INT, Losses INT, Scored INT, Conceded INT, Points INT) CREATE TABLE 2007_2008_table (2007_2008_table_id AUTO_INCREMENT PRIMARY KEY, Club VARCHAR, Played VARCHAR, Won VARCHAR, Drawn VARCHAR, Lost VARCHAR, Points for VARCHAR, Points against VARCHAR, Tries for VARCHAR, Tries against VARCHAR, Try bonus VARCHAR, Losing bonus VARCHAR, Points VARCHAR) CREATE TABLE doubles_finals_8 (doubles_finals_8_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Tournament VARCHAR, Surface VARCHAR, Partner VARCHAR, Opponents in the final VARCHAR, Score VARCHAR) CREATE TABLE round_four (round_four_id AUTO_INCREMENT PRIMARY KEY, Pick # INT, CFL Team VARCHAR, Player VARCHAR, Position VARCHAR, College VARCHAR) CREATE TABLE us_ratings (us_ratings_id AUTO_INCREMENT PRIMARY KEY, # INT, Airdate VARCHAR, Episode VARCHAR, Rating VARCHAR, Share INT, Rating/Share (18–49) VARCHAR, Viewers (millions) VARCHAR, Rank (Timeslot) INT, Rank (Night) INT)  
SELECT Date FROM doubles_finals_8 WHERE Surface = hard AND Partner = tom mercer